Toronto's closer used a combination of fastballs, sliders and changeups during the brief workout at Florida Auto Exchange Stadium.
"I felt all right," Janssen said. "It was good to get out there, good to compete. Still by no means a finished product, but it's another step in the right direction and it was nice to face some hitters and pick up the intensity again."
Janssen had yet to face batters this spring following offseason surgery that involved shaving down the collarbone in his right shoulder. The procedure was described as relatively minor, but it included a rather extensive rehab that has put Janssen's start to the season somewhat in doubt.
The 31-year-old remains optimistic that he'll be ready for Opening Day, but he likely will need to pitch in at least one Minor League game and several Grapefruit League games in order for that to happen.
The timing will be tight for Toronto's first game on April 2 vs. the Indians. Janssen's hopeful, but there are mental and physical barriers he must overcome before that can occur.
"Physical, because you have to challenge the arm and see how it comes back," Janssen said. "See the recovery, see what kind of velocity it is, if it needs to get harder or whatever.
"Mentally, as every day goes on, if there's good progress then I feel more inclined to throw harder and challenge it even more. Where, if you still have that little bit of doubt in the back of your mind, you're still guarding just a touch."
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.